As shown in FIG. 1, a bicycle V-type brake 10 of the prior art is composed of two brake arms 10A, two brake shoes 10B, a curved tube 10C, a curved tube fastening seat 10D, and a brake cable 10E, The brake cable 10E is fastened at one end thereof with a brake lever (not shown in the drawing).
As shown in FIG. 2, before the brake shoe 10B is in contact with the bicycle wheel rim, the grip force (F) of the brake lever is constant, as indicated by a line "A" in FIG. 2. As soon as the brake shoe 10B makes contact with the bicycle wheel rim, the grip force (F) increases rapidly, as shown by the line "B" in FIG. 2. There is a considerably small lever stroke (S1), which is the distance between a contact point (C) of the brake shoe 10B with the wheel rim and a lock-up point (D) of the brake shoe 10B with the wheel rim. That is to say that the lever stroke (S1) takes place in a relatively short period of time, thereby unabling the bicyclist to respond in time to avert the overturning of the bicycle.
With a view to overcoming the drawbacks of the prior art bicycle brake described above, this inventor of the present invention disclosed an improved version of the bicycle V-type brake consisting of two brake arms which are fastened pivotally together. The improved version is not compatible with the prior art bicycle brake in term of the specifications and must be therefore further improved.